service.c

   1 /*
   2  * Copyright (C) 2014 John Crispin <blogic@openwrt.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License version 2.1
   6  * as published by the Free Software Foundation
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <sys/types.h>
  15 #include <arpa/nameser.h>
  16 #include <sys/socket.h>
  17
  18 #include <resolv.h>
  19 #include <glob.h>
  20 #include <stdio.h>
  21 #include <time.h>
  22
  23 #include <libubus.h>
  24 #include <libubox/vlist.h>
  25 #include <libubox/uloop.h>
  26 #include <libubox/avl-cmp.h>
  27 #include <libubox/blobmsg_json.h>
  28
  29 #include "ubus.h"
  30 #include "dns.h"
  31 #include "service.h"
  32 #include "util.h"
  33 #include "interface.h"
  34 #include "announce.h"
  35
  36 enum {
  37         SERVICE_SERVICE,
  38         SERVICE_PORT,
  39         SERVICE_TXT,
  40         __SERVICE_MAX,
  41 };
  42
  43 struct service {
  44         struct vlist_node node;
  45
  46         time_t t;
  47
  48         const char *id;
  49         const char *service;
  50         const uint8_t *txt;
  51         int txt_len;
  52         int port;
  53         int active;
  54 };
  55
  56 static const struct blobmsg_policy service_policy[__SERVICE_MAX] = {
  57         [SERVICE_SERVICE] = { .name = "service", .type = BLOBMSG_TYPE_STRING },
  58         [SERVICE_PORT] = { .name = "port", .type = BLOBMSG_TYPE_INT32 },
  59         [SERVICE_TXT] = { .name = "txt", .type = BLOBMSG_TYPE_ARRAY },
  60 };
  61
  62 static void
  63 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
  64                struct vlist_node *node_old);
  65
  66 static struct blob_buf b;
  67 static VLIST_TREE(services, avl_strcmp, service_update, false, false);
  68 static int service_init_announce;
  69
  70 static const char *
  71 service_name(const char *domain)
  72 {
  73         static char buffer[256];
  74
  75         snprintf(buffer, sizeof(buffer), "%s.%s", mdns_hostname, domain);
  76
  77         return buffer;
  78 }
  79
  80 static void
  81 service_add_ptr(const char *host, int ttl)
  82 {
  83         int len = dn_comp(host, mdns_buf, sizeof(mdns_buf), NULL, NULL);
  84
  85         if (len < 1)
  86                 return;
  87
  88         dns_add_answer(TYPE_PTR, mdns_buf, len, ttl);
  89 }
  90
  91 static void
  92 service_add_srv(struct service *s, int ttl)
  93 {
  94         struct dns_srv_data *sd = (struct dns_srv_data *) mdns_buf;
  95         int len = sizeof(*sd);
  96
  97         len += dn_comp(mdns_hostname_local, mdns_buf + len, sizeof(mdns_buf) - len, NULL, NULL);
  98         if (len <= sizeof(*sd))
  99                 return;
 100
 101         sd->port = cpu_to_be16(s->port);
 102         dns_add_answer(TYPE_SRV, mdns_buf, len, ttl);
 103 }
 104
 105 #define TOUT_LOOKUP     60
 106
 107 static time_t
 108 service_timeout(struct service *s)
 109 {
 110         time_t t = monotonic_time();
 111
 112         if (t - s->t <= TOUT_LOOKUP)
 113                 return 0;
 114
 115         return t;
 116 }
 117
 118 static void
 119 service_reply_single(struct interface *iface, struct sockaddr *to, struct service *s, int ttl, int force)
 120 {
 121         const char *host = service_name(s->service);
 122         char *service = strstr(host, "._");
 123         time_t t = service_timeout(s);
 124
 125
 126         if (!force && (!s->active || !service || !t))
 127                 return;
 128
 129         service++;
 130
 131         s->t = t;
 132
 133         dns_init_answer();
 134         service_add_ptr(service_name(s->service), ttl);
 135         dns_send_answer(iface, to, service);
 136
 137         dns_init_answer();
 138         service_add_srv(s, ttl);
 139         if (s->txt && s->txt_len)
 140                 dns_add_answer(TYPE_TXT, (uint8_t *) s->txt, s->txt_len, ttl);
 141         dns_send_answer(iface, to, host);
 142 }
 143
 144 void
 145 service_reply(struct interface *iface, struct sockaddr *to, const char *match, int ttl)
 146 {
 147         struct service *s;
 148
 149         vlist_for_each_element(&services, s, node) {
 150                 if (!match || !strcmp(s->service, match))
 151                         service_reply_single(iface, to, s, ttl, 0);
 152         }
 153 }
 154
 155 void
 156 service_announce_services(struct interface *iface, struct sockaddr *to, int ttl)
 157 {
 158         struct service *s;
 159
 160         vlist_for_each_element(&services, s, node) {
 161                 s->t = 0;
 162                 if (ttl) {
 163                         dns_init_answer();
 164                         service_add_ptr(s->service, ttl);
 165                         dns_send_answer(iface, to, C_DNS_SD);
 166                 }
 167                 service_reply_single(iface, to, s, ttl, 0);
 168         }
 169 }
 170
 171 static void
 172 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
 173                struct vlist_node *node_old)
 174 {
 175         struct interface *iface;
 176         struct service *s;
 177
 178         if (!node_old) {
 179                 s = container_of(node_new, struct service, node);
 180                 if (service_init_announce)
 181                         vlist_for_each_element(&interfaces, iface, node) {
 182                                 s->t = 0;
 183                                 service_reply_single(iface, NULL, s, announce_ttl, 1);
 184                         }
 185                 return;
 186         }
 187
 188         s = container_of(node_old, struct service, node);
 189         if (!node_new && service_init_announce)
 190                 vlist_for_each_element(&interfaces, iface, node)
 191                         service_reply_single(iface, NULL, s, 0, 1);
 192         free(s);
 193 }
 194
 195 static void
 196 service_load_blob(struct blob_attr *b)
 197 {
 198         struct blob_attr *txt, *_tb[__SERVICE_MAX];
 199         struct service *s;
 200         char *d_service, *d_id;
 201         uint8_t *d_txt;
 202         int rem2;
 203         int txt_len = 0;
 204
 205         blobmsg_parse(service_policy, ARRAY_SIZE(service_policy),
 206                 _tb, blobmsg_data(b), blobmsg_data_len(b));
 207         if (!_tb[SERVICE_PORT] || !_tb[SERVICE_SERVICE])
 208                 return;
 209
 210         if (_tb[SERVICE_TXT])
 211                 blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2)
 212                         txt_len += 1 + strlen(blobmsg_get_string(txt));
 213
 214         s = calloc_a(sizeof(*s),
 215                 &d_id, strlen(blobmsg_name(b)) + 1,
 216                 &d_service, strlen(blobmsg_get_string(_tb[SERVICE_SERVICE])) + 1,
 217                 &d_txt, txt_len);
 218         if (!s)
 219                 return;
 220
 221         s->port = blobmsg_get_u32(_tb[SERVICE_PORT]);
 222         s->id = strcpy(d_id, blobmsg_name(b));
 223         s->service = strcpy(d_service, blobmsg_get_string(_tb[SERVICE_SERVICE]));
 224         s->active = 1;
 225         s->t = 0;
 226         s->txt_len = txt_len;
 227         s->txt = d_txt;
 228
 229         if (_tb[SERVICE_TXT])
 230                 blobmsg_for_each_attr(txt, _tb[SERVICE_TXT], rem2) {
 231                         int len = strlen(blobmsg_get_string(txt));
 232                         if (!len)
 233                                 return;
 234                         if (len > 0xff)
 235                                 len = 0xff;
 236                         *d_txt = len;
 237                         d_txt++;
 238                         memcpy(d_txt, blobmsg_get_string(txt), len);
 239                         d_txt += len;
 240                 }
 241
 242         vlist_add(&services, &s->node, s->id);
 243 }
 244
 245 static void
 246 service_load(char *path)
 247 {
 248         struct blob_attr *cur;
 249         glob_t gl;
 250         int i, rem;
 251
 252         if (glob(path, GLOB_NOESCAPE | GLOB_MARK, NULL, &gl))
 253                 return;
 254
 255         for (i = 0; i < gl.gl_pathc; i++) {
 256                 blob_buf_init(&b, 0);
 257                 if (blobmsg_add_json_from_file(&b, gl.gl_pathv[i])) {
 258                         blob_for_each_attr(cur, b.head, rem)
 259                                 service_load_blob(cur);
 260                 } else {
 261                         fprintf(stderr, "Error reading %s JSON\n", gl.gl_pathv[i]);
 262                 }
 263         }
 264         globfree(&gl);
 265 }
 266
 267 static void
 268 service_init_cb(struct ubus_request *req, int type, struct blob_attr *msg)
 269 {
 270         struct blob_attr *cur;
 271         int rem;
 272
 273         get_hostname();
 274
 275         vlist_update(&services);
 276         service_load("/etc/umdns/*");
 277
 278         blob_for_each_attr(cur, msg, rem) {
 279                 struct blob_attr *cur2;
 280                 int rem2;
 281
 282                 blobmsg_for_each_attr(cur2, cur, rem2) {
 283                         struct blob_attr *cur3;
 284                         int rem3;
 285
 286                         if (strcmp(blobmsg_name(cur2), "instances"))
 287                                 continue;
 288
 289                         blobmsg_for_each_attr(cur3, cur2, rem3) {
 290                                 struct blob_attr *cur4;
 291                                 int rem4;
 292                                 int running = 0;
 293
 294                                 blobmsg_for_each_attr(cur4, cur3, rem4) {
 295                                         const char *name = blobmsg_name(cur4);
 296
 297                                         if (!strcmp(name, "running")) {
 298                                                 running = blobmsg_get_bool(cur4);
 299                                         } else if (running && !strcmp(name, "data")) {
 300                                                 struct blob_attr *cur5;
 301                                                 int rem5;
 302
 303                                                 blobmsg_for_each_attr(cur5, cur4, rem5) {
 304                                                         struct blob_attr *cur6;
 305                                                         int rem6;
 306
 307                                                         if (strcmp(blobmsg_name(cur5), "mdns"))
 308                                                                 continue;
 309
 310                                                         blobmsg_for_each_attr(cur6, cur5, rem6)
 311                                                                 service_load_blob(cur6);
 312                                                 }
 313                                                 break;
 314                                         }
 315                                 }
 316                         }
 317                 }
 318         }
 319         vlist_flush(&services);
 320 }
 321
 322 void
 323 service_init(int announce)
 324 {
 325         get_hostname();
 326
 327         service_init_announce = announce;
 328         ubus_service_list(service_init_cb);
 329 }
 330
 331 void
 332 service_cleanup(void)
 333 {
 334         vlist_flush(&services);
 335         blob_buf_free(&b);
 336 }